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// ---
// Author: Jeffrey Junfeng Pan (panjunfeng@gmail.com)
// Credit: Miklos Erdelyi (the original author)

// Interface for processing mined frequent patterns.

#ifndef FP_GROWTH_PATTERN_WRITER_H_
#define FP_GROWTH_PATTERN_WRITER_H_

#include "itemsets.h"

namespace frequent_pattern_mining {

// PatternWriter interface.
template <typename T>
class PatternWriter {
 public:
  virtual ~PatternWriter() {}
  // Called whenever a frequent pattern is extracted.
  virtual void WritePattern(const ItemsetFrequencyPair<T>& pattern) = 0;
};

// PatternWriter implementation which stores mined patterns in an in-memory
// buffer of Itemsets.
template <typename T>
class PatternWriterMemoryImpl : public PatternWriter<T> {
 public:
  explicit PatternWriterMemoryImpl(Itemsets<T>* output) : output_(output) {}

  void WritePattern(const ItemsetFrequencyPair<T>& pattern) {
    output_->InsertItemset(pattern);
  }
 private:
  Itemsets<T>* output_;
};

}  // namespace frequent_pattern_mining

#endif  // FP_GROWTH_PATTERN_WRITER_H_
